I'm a little skeptical of this newest Switch 2 leak. While it would be great to have a Switch 1 card slot, it raises alot of questions. Switch 2 needs fast storage, it can't have last gen storage speeds again, and I'm doubtful that Nintendo will be able to get faster Switch 2 carts and slower Switch 1 carts to work in the same slot, which would mean they would need 2 cart slots, which seems fairly pricey to me. On top of that, physical carts with the kind of transfer speeds and sizes that Nintendo is going to need for next gen games (at least 50 GB to fit the larger next gen games, and at least 1 GB/s in transfer speed I'd assume, considering Xbox Series is like 2.4 GB/s and PS5 5.5 GB/s) seem like they would be prohibitively expensive to produce, unless Nintendo plans to charge $10 more for physical Switch 2 games than on digital.
It seems to me like they're going to have to either make a choice of either making a console with a very high bill of materials and expensive carts that end up cutting into their profit alot, or make the choice to have last gen storage speeds, which is going to make porting PS5/XS games to Switch 2 nearly as difficult as porting PS4/XB1 games to Switch 1 was, or make the choice to go digital only on Switch 2 games.